Intravenously injected FK506 failed to inhibit hippocampal calcineurin

Motohiro Morioka, Kohji Fukunaga, Yutaka Kai, Tatemi Todaka, Shigetoshi Yano, Jun ichiro Hamada, Eishichi Miyamoto, Yukitaka Ushio

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


FK506 (tacrolimus) is known as an inhibitor for calcineurin and is used in numerous research fields. It is not clear whether intravenously injected FK506 inhibits neuronal calcineurin. We measured the calcineurin activities of normal and postischemic rat hippocampi after intravenous injection of FK506 (3 mg/kg). Intravenously injected FK506 had no inhibitory effect on calcineurin activity in the hippocampi of normal and postischemic rats, whereas FK506 inhibited the calcineurin in vitro (purified enzyme, hippocampal homogenate, and hippocampal slice culture homogenate). Thus, it is considered that intravenously injected FK506 does not act on intraneuronal calcineurin and that several effects of FK506 are not due to the inhibition of neuronal calcineurin.

Original languageEnglish
Pages (from-to)802-806
Number of pages5
JournalBiochemical and biophysical research communications
Issue number4
Publication statusPublished - 2001
Externally publishedYes


  • Calcineurin
  • FK506
  • Hippocampus

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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